since gnome3 the webkit library name changed from libwebkit-1.0.so to libwebkitgtk-1.0.so, so I did
# cd /usr/lib
# ln -s libwebkitgtk-1.0.so libwebkit-1.0.so.2
and
-Dorg.eclipse.swt.browser.UseWebKitGTK=true
works again